A stereoscopic system in which an image for a left eye and an image for a right eye, having a given disparity therebeween, are combined and displayed is well known. A viewer wears complementary color glasses or polarized glasses, or uses a lenticular lens or a parallax barrier to partially block his/her vision to thereby cause binocular disparity.
A set of disparity images is typically created by imaging one object from two different viewpoints. However, a set of disparity images can be created from one image taken from a single viewpoint, as is suggested in Patent Document 1. A stereoscopic image generator described in Patent Document 1 calculates depth-values from saturations of pixels forming an image, discriminates on the basis of the depth-values (or corrected depth-values) between a near view and a distant view of the image, and enlarges a disparity between an image for a left eye and an image for a right eye in the near view than in the distant view. The algorithm of calculating a depth-value from saturation of a pixel is employed in view of an empirical rule that generally a more distant scene has a lower saturation and a nearer scene has a higher saturation.
Owing to techniques such as that described in Patent Document 1, it has recently become relatively easy to create, from one image, images which have a given disparity there between. Accordingly, it is expected that video content not originally intended for stereoscopic vision will in future be subject to a stereoscopic imaging process and marketed in a computer readable medium such as a DVD (Digital Video Disc). A purchaser of such a DVD will be able to view the video content as stereoscopic images using a computer.    Patent Document 1: Unexamined Patent Publication No. 2002-123842.